Elastic fluid power plant



June 11, 1940. s. B. WARREN ELASTIC FLUID POWER PLANT Filed Dec. 8, 193B Inventor 1 Glenn B. Waffen, byjvzwjw Patented 'une 11, 1940 UNITED STATES ELASTIC FLUID POWER PLANT Glenn B. Warren, Niskayuna, N. Y., assigner to General Electric Company, a corporation o! New York Application December 8, 1938, Serial No. 244,624

10 Claims.

I'he present invention relates to elastic iluid power plants in which elastic fluid, for instance, steam or vapor, is produced in an elastic fluid generator and consumed in the consumer. 'I'he I elastic fluid generator usually comprises a boiler in which the liquid is heated and evaporated, a furnace for heating the boiler and means for supplying and controlling the supply of fuel and' air to the furnace. The consumer may comprise l an elastic fluid turbine, means for conducting and regulating the ilow of elastic iluid to theturbine and means including a condenser for receiving exhaust fluid from the turbine. The means for supplying and regulating the supply of feed fluid to the boiler and the means for supplying combustible material and air to the furnace may include pumps and a blower driven by an auxiliary motor such `as an elastic fluid turbine receiving operating fluid from the boiler.

The object oi the present invention is to provide an improved arrangement for power plants of the type specified whereby the control and regulation of the various apparatus is accomplished in a simple manner.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto taken in connection with the accompanying drawing.

In the drawing, Fig. 1 illustrates, in a diagrammatic form, a power plant embodying one .form of my invention, and Fig. 2 illustrates a modiiication of the arrangement for controlling the supply of elastic fluid tothe main turbine.

In the drawing I have shown a power plant system in a diagrammatic form only, omitting, for the sake of clarity, supplemental apparatus such as pilot valves, valve actuating motors and other incidental control equipment which may be sup- 40 plied as required by 'one skilled in the art.

In the drawing, I! indicates an elastic fluid generator comprising a furnace and a boiler of .the pumped through type which supplies elastic fluid through a conduit II to an auxiliary turbine I2, the exhaust from which is conducted to a main turbine I3 connected to any suitable load, not shown. 'I'he exhaust from the main'turbine is fed into suitable condensing apparatus indicated at Il, the condensate from the reservoir or hot-well I5 being returned to the boiler by a booster pump Il through a conduit I1, boiler feed pump I 8 and conduit I3. It is, of course, understood that other control equipment may be embodied in the boiler feed water system as desired without departing from the scope of this invention. The auxiliary turbine I2 is arranged for driving, as by shaft 20, the auxiliaries including the boiler feed Water pump Il, and also a furnace fuel pump 2|, and a furnace' combustion air blower 22. Although these auxiliaries are shown 5 as directly driven by the shaft 20, it is understood that suitable speed reduction devices may be embodied in the driving connection as desired.

It is obvious that the quantity of water, fuel, and air supplied to the boiler and furnace, respec- 10 tively, and hence, the elastic fluid output of the generator will vary as' the speed of the auxiliary turbine, which in turn will vary in speed in accordance with the demand for elastic fluid as determined by the load on the main`turbine as will l5 be more fully described hereinafter.

The supply of elastic fluid is admitted to the auxiliary turbine I2 preferably through a plurality of sectional admission valves', indicated at e 23, which may be of any form well known in the 20 art. 'I'he sectional admission valves may be biased to the closed position by means of springs 2| and adapted to be opened in sequential order by means of the lift bar 25 which is operated by a suitable fluid pressure motor such as that 25 indicated at 26. As shown, this valve actuating motor comprises a cylinder 21 having a piston 28 slidably arranged therein and connected as by stem 29 to the valve lifting bar 25. A suitable spring 3U is arranged within the cylinder 2'I above 30 the piston 28 for biasing it inthe downward direction. The connection 3l communicates between the elastic iluid supply conduit II and the lower end of the cylinder, whereby the piston is forced upwardly in accordance with the pressure of the 35 elastic iluid supply, the valves 23 being thereby so regulated as to maintain substantially constant the pressure of the supply.

The exhaust from the auxiliary turbine I2 is fed by conduit means 32 to the main turbine 4 I3. Suitable admission valve means 33 is arranged in the inlet of the main turbine I3 for controlling the supply of elastic fluid thereto 'which is adapted for adjustment in accordance with the load on the turbine I3 and also for 45 supplemental adjustment in accordance with overspeed conditions of the auxiliary turbine I2. As indicated, the valve stem 3l may be connected to a floating lever 35, one end of which is adapted to be adjusted in accordance with load require- 50 ments by any well known form of control means such as by a manual controller as indicated at 36. The other end of the lever 35 is adapted for supplemental control by a speed governor mechanism 31 arranged to be driven from the 55 shaft of the auxiliary turbine through gearing 33. It isunderstood that the governor 3'| is normally ineffective, it being so adjusted that its weights will arise only upon a predetermined overspeed of theauxlliary turbine to move the valve 33 to a more closed position.

The operation of the power plant as thus far described is as follows: Assume that the power plant is operating in equilibrium with normal conditions obtaining. During such operation, the valve 33 is in an opened position and a supply of elastic fluid is fed to the main turbine in a quantity sufficient to take care of the load con- 4nected thereto. During the condition of Vequilibrium assumed, the speed of the auxiliary turbine is proportional to the flow of steam to the turbine I3 and the feed water pump, the fuel pump and the combustion air blower are driven at a speed that such a quantity of steam is generated in the boiler I0 as is required by the load on the system. Now, assume that the load on the main turbine I3 is increased whereupon the controller 36 is operated to move the valve 33 to a more opened position to increase the supply of elastic fluid thereto. The back pressure of the auxiliary turbine I2 will drop causing it to accelerate due to the greater pressure drop therethrough. The speed of the boiler auxiliaries is also increased, thereby supplying more fuel and combustion air to the furnace and more feed Water for the generation of a greater supply of elastic fluid to accommodate theincreased load demand.

As the back pressure to the auxiliary turbine drops, the ow of steam through its valves 23 will increase tending to cause a reduction in pressure in the supply conduit I I.v This tendency will be met by a slight throttling of the valves 23 to maintain the pressure constant in the conduit II. The auxiliary turbine, however, will continue to operate at a speed somewhat greater than that prior to the change. With a slight time lag, depending' upon the response characteristics of the boiler I0, the supply of elastic iluid therefrom will be increased, raising the pressure in the supply conduit I I. The device 26 responsive to this increase of pressure, will open additional valves of the auxiliary turbine increasing the supply of elastic fluid therethrough and to the main turbine I3 to enable the latter to carry properly the increased burden. The increased ilow of elastic fluid through the auxiliary turbine will have little eiect upon the speed thereof, for as the flow is increased, the back pressure will vaccordingly increase, so that the net pressure drop therethrough will remain substantially unchanged. As the supplypf elastic fluid fed to the turbine I3 approaches that required for the new condition of load, the valve 33 may be 'throttled somewhat by the controller 36. This :movement of the valve 33, however, further increases the back pressure of the auxiliary turbine, reducing the pressure drop thereacross causing it .to decrease somewhat in speed and accordingly slightly decrease the supply of fuel, combustion air and feed water to the boiler and to stabilize its output of elastic fluid in accordance with the new lload level.

converse manner as described above. a decrease in the output of elastic fluid from the generator I3.

Should the main turbine admission valve 33 be suddenly actuated to a wide open position in response to a sudden increase in the load on the turbine I3, the sudden removal of the back pressure to the auxiliary turbine I2 may cause it to accelerate rapidly to an excessive speed likely to cause injury to itself or to the auxiliaries connected thereto.` To preclude such excessive speed of the auxiliary turbine, the governor meehanism 31, driven by the shaft 23, is so adjusted that upon the occurrence of a predetermined maximum safe speed the valve 33 is moved thereby to a throttling position thereby bringing about an increase in the back pressure to the auxiliary turbine and the maintenance of a safe speed thereof.

In Fig. 2 is shown a modification of the arrangement for controlling the supply of elastic fluid to the main turbine, in which like parts are given the same reference characters as in Fig. l. In this modification, the valve 33 is arranged for individual adjustment as by hand wheel 43, or

in anyy other well known manner. A second an excessive speed condition of the auxiliary turbine, as in the modification described above.

Although the major changes in the output of the elastic uid generator auxiliaries are taken care of automatically in response to variations in load conditions by the increase and decrease in speed of the auxiliary turbine, secondary adjustments in the ratio of the air, fuel and boiler liquid supplied to the elastic fluid'generator are preferably made by supplementary control. This may be effected by controlling the supply of combustibles to the furnace in accordance with the level of liquid in the boiler as supplied by the boiler feed pump. As indicated in the drawing, a drum 45 of the boiler, the liquid level in which damper arranged in the air supply conduit 5I extending from the blower 22 to the furnace of the elastic uid generator I3. The proper ratio between the alr passed by the damper 53 and the fuel supplied to the furnace is regulated by means including flow responsive devices 52 and 53. The device 52 comprises a casing 54 having a flexible diaphragm 55 arranged therein forming chambers on opposite sides thereof with the casing. The chamber onv the right of the diaphragm is in communication by conduit 55 with the air supply conduit 5I ahead of a nomle 51 provided therein. The chamber on the left of the diaphragm is in communication by conduit 53 with the air supply conduit 5I behind the nozzle 51 as regards the air ilow therethrough. vSimilar to the device 52, the device 53 comprises a casing 53 having a flexible diaphragm GII arranged therein forming chambers on the opposite sides thereof with the casing. 'I'he chamber on the left is in communication by conduit 3| with the fuel supply conduit B2 ahead of a nozzle 53 provided therein. The chamber on the right is in communication by conduit 64 with the fuel supply conduit 62 behind the nozzle 63 as regards the direction of fuel flow therethrough. It is to be understood Yis to be held constant, is provided with a float tion corresponding to the rate of iiow through the associated conduits. With the connections asindicated, the stem 65 of device 52 is adapted to be moved to the left by an increased air flow whereas stem 66 of the device 53 is adapted to be moved to the right by an increased fuel oil flow. The stems 65 and 66 secured to the diaphragms 55 and 60 of the devices 52 and 53, respectively, are connected together by means of a floating lever 61. The floating lever is pivotally connected intermediate its ends as at 63 to one end of a lever 694 which is pivoted at the other end to a stationary part 10. Movement of the lever 69 is imparted by a connection link 1I to the valve 12 arranged in the fuel supply conduit 62 between the fuel pump 2| and the nozzle 63. In the event that the output of the fuel pump 2| is in excess of that allowed to pass the valve 12 provision is made by means of conduit 13 for bypassing the excess fuel from the conduit 62 back to the fuel storage tank 14. A pressure relief valve 15 is arranged in the by-pass conduit which may be adjusted to open upon a predetermined pressure obtaining in the conduit 62 between the fuel pump 2I and the valve 12.

By operation of the supplementary control apparatus described, should the liquid in the drum 45 fall below a predetermined level, the supply of both fuel and air to the furnace will be decreased. More specifically, a decrease of the liquid level in the drum 45 causes downward movement of the float 46 whereby the bell crank 48 is turned in clockwise direction, causing movement of the link 49 to the right, resulting in movement of the valve 50 towards closing position. This reduces the flow of combustion air to the furnace. Due to the decreased flow of air through the restriction 51 the diaphragm 55 of the flow-responsive device is moved towards the right, causing clockwise turning movement of the link 61 about its connection with the link 66 whereby the lever 69- is also moved in clockwise direction about the fulcrum 10, thus causing closing movement of the valve 12 and reduced flow of fuel through the pipe 62. Under such condition the output or pressure of elastic uid from the generator I0 will decrease causing the valves 23 to move to a slightly more closed position. Since the main turbine I3 will be effected by this decrease in steam to decrease in speed, the controller 36 will be actuated to adjust the valve 33 to a more opened position. As described above, an opening of the valve 33 causes a decrease in the back pressure to the auxiliary turbine I2 resulting in an increase of its speed whereupon the output of the lboiler liquid feed pump I8 will be increased to bring the level of the liquid in the drum 45 up to a predetermined position. As the level in the drum 45 rises, the supply of air and fuel to the furnace is gradually increased resulting in an increase in the generation of elastic fluid whereupon a normal condition of equilibrium will be reestablished in the power plant system.

Should the level of liquid in the drum 45 rise above a predetermined position, the supply of fuel and air to the furnace will be accordingly increased resulting in an increase in the generation of elastic fluid. During a rise of the level Vin the drum 45 the operation of the mechanisms actuating valves 50 and 12 is the same as described above in connection with a drop of the liquid level in the drum 45 except that the various elements move in opposite direction. `The increase of pressure in the supply conduit I| will cause the valves 23 to moveto a more opened position passing more elastic fluid therethrough and through the auxiliary turbine. However, since the valve 33 will be so throttled as to pass only the amount of elastic fluid as is required for the instant load, the pressure in conduit 32 will increase to decrease the pressure drop through the auxiliary turbine. Accordingly, the auxiliary turbine will decrease somewhat in speed, to decrease the supply of feed liquid to the boiler which in turn will result in a decrease in -the-supply of combustibles to the furnace. Upon the normal level of liquid obtaining in the drum 31, the system will again be stabilized in a condition of operational equilibrium.

Having described the method of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried-out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In a power plant, the combination of an elastic fluid generator comprising a furnace, a boiler, a fuel pump, a combustion air blower and a boiler feed pump, an auxiliary turbine for driving said pumps and said blower, conduit means for conducting elastic uid from said boiler to said auxiliary turbine, valve means in said conduit for controlling the admission of elastic fluid to said auxiliary turbine, means for adjusting said valve means to maintain substantially constant fluid pressure in said conduit means, a main turbine, conduit means for conducting elastic fluid from said auxiliary turbine to said main turbine including valve means for controlling the flow of elastic fluid to said main turbine, means for adjusting said last mentioned valve means in response to conditions of load on said main turbine, means for adjusting the flow of elastic fluid to said main turbine in response to a predetermined speed of said auxiliary turbine, and means for adjusting the supply of combustibles to said furnace in response to changes of the liquid level in said boiler.

2. In a power plant, the combination of an elastic iiuid generator comprising a furnace, -a boiler, a boiler feed pump, a fuel pump and a combustion air blower, an auxiliary turbine for driving said pumps and saidvblower, conduit means for conducting elastic fluid from said boiler to said auxiliary turbine, valve means for adjusting the supply of elastic fluid to said auxiliary turbine, means for positioning said valve means in response to the fluid4 pressure in said conduit means, a main turbine, conduit means for conducting elastic fluid from said auxiliary turbine to said main turbine, valve means in said last mentioned conduit means for controlling the ow of elastic fluid to said main turbine in response to conditions` of load on said main turbine, additional valve means in said last mentioned conduit means, and means for adjusting said additional valve means toward the closed position in response to a predetermined overspeed condition of said auxiliary turbine.

3. In a power plant, the combination of an elastic fluid generator comprising a furnace, a boiler, a boiler feed pump, a fuel pump and a combustion air blower, an auxiliary turbine for driving said pumps and said blower, conduit means for conducting elastic fluid from said boiler to said auxiliary turbine, valve means for adjusting the supply of elastic fluid to said auxiliary turbine, means for positioning said valve means in response to the fluid pressure in said conduit means, a main turbine, conduit means for conducting elastic fluid from said auxiliary turbine to said main turbine including valve means for controlling the flow of elastic fluid to said main turbine in response to'conditions of load on said main turbine, and means for adjusting said last mentioned valve means toward the closed direction in response to a predetermined overspeed condition of said auxiliary turbine.

4. In a power. plant, the combination of an elastic fluid generator comprising a furnace, a boiler, a boiler feed pump, a fuel pump and a combustion air blower, an auxiliary turbine for driving said pumps and said blower, conduit means for conducting elastic fiuid from said boiler to said auxiliary turbine, valve means in said conduit means for adjusting the ilow of elastic uid to said auxiliary turbine, means for positioning said valve means in response to the elastic fluid pressure in said conduit means, a main turbine, conduit means for conducting elastic fluid from said auxiliary turbine to said main' turbine including valve means for controlling the flow of elastic fluid to said main turbine, and means for adjusting the supply 'of combustibles to said furnace in response to changes of the liquid level in said boiler.

5. In a power plant, the combination of an elastic fluid generator comprising a furnace, a boiler, .a fuel pump and a boiler feed pump, an auxiliary turbine for driving said pumps, conduit means for conducting elastic fluid from `said boiler to said auxiliary turbine, valve means in said conduit, means for positioning said valve means in response to the fluid pressure in said conduit means, a main turbine, conduit means for conducting elastic fluid from said auxiliary turbine to said main turbine including valve means for controlling the flow of elastic uid to said main turbine, and normally inoperative means for reducing said ilow of elastic fluid to said main turbine in response to a predetermined excess speed of said auxiliary turbine.

6. In a power plant, the combination of a main turbine, an elastic uid generator comprising a furnace, a boiler, a fuel pump and a boiler :feed pump, an auxiliary turbine for driving said pumps, a conduit means for conducting elastic fluid from said boiler to said auxiliary turbine, valve means in said conduit for adjusting the flow of elastic uid to said auxiliary turbine,A

means for positioning said valve means inA response to uid pressure in said conduit means ahead of said valve means, conduit means for conducting elastic fluid from said auxiliary turbine to said main turbine including valve means for controlling the flow of elastic uid to said main turbine, and mechanism responsive to a predetermined speed of the auxiliary turbine foi' positioning the last named valve means. A

7. In a power plant, the combination of a main turbine, an elastic fluid generator comprising a furnace, a boiler, a fuel pump, a combustion air blower and a boiler feed pump, an auxiliary turbine for driving said pumps and said blower, conduit means for conducting' elastic fluid from said boiler to said auxiliary turbine, valve means for adjusting the flow of elastic fluid to said auxiliary turbine, conduit means for conducting elastic fluid from said auxiliary turbine to said main turbine including valve means for controlling the flow of elastic fluid to said main turbine, and an overspeed governor driven from the auxiliary turbine for positioning the last mentioned valve means.

8. In combination, a source of elastic fluid, a first turbine connected to said source, sectional admission valves for said turbine, pressure responsive means for controlling said valves so as to maintain substantially constant the pressure of elastic fluid from said source, a second turbine mechanically independent oi' the first turbine connected for directly receiving the exhaust from said first turbine, an admission valve for controlling the elastic fluid flow from said first turbine to said second turbine, and means responsive to a predetermined speed of said first turbine for regulating the flow of elastic uid to said second turbine.

9. In combination, a source of elastic fluid, a first turbine connected to said source, admission valves for said turbine, pressure responsive means for controlling said valves so as to maintain substantially constant.the pressure of elastic fluid from said source, a second turbine mechanically independent of the first turbine connected for directly receiving the exhaust from said first turbine, an admission valve for controlling the elas-l tic fluid flow from said rst turbine to said second turbine, means for regulating said second turbine admission valve in accordance with the load on said second turbine, and means responsive to a predetermined speed of said first turbine for adjusting the admission valve of said second turbine.

10. In combination, a source of elastic fluid, a turbine connected to said source, admission valves for said turbine, pressure responsive means for controlling said valves so as to maintain substantially constant the pressure of elastic fluid from said source, other elastic fluid consuming apparatus mechanically independent of the turbine connected for directly receiving the exhaust from said turbine, a valve for regulating the ow of elastic fluid from said turbine to said other apparatus in accordance with the elastic fluid demand by said other apparatus, and means responsive to a predetermined speed of said turbine for supplementally adjusting said last mentioned valve.

GLENN B. WARREN. 

